The aim of these investigations is to employ immunologic methods to characterize the surface structures on malignant human lymphoid cells with the goals of increasing our understanding of the pathophysiology of the malignant process and establishing a basis for the rational design of specific therapies. We plan to continue our studies of the cellular distribution, function, and chemical nature of tumor-associated antigens defined by monoclonal antibodies on malignant lymphoid cells. We will study the expression the common acute lymphoblastic leukemia antigen (CALLA) on terminally differentiated myeloid cells with the goals of determining whether or not granulocytes synthesize the antigen detected on their surface, how closely the glycoprotein on granulocytes resembles that on ALL cells, and whether or not antibodies to CALLA can inhibit the specialized functions of this cell population (chemotaxis, phagocytosis, degranulation, and killing). We are also exploring new methods for making additional monoclonal antibodies to CALLA, having demonstrated that all seven such antibodies tested react with a single and apparently highly immunogenic region of this large molecule. Such reagents will help us to determine whether or not the distribution of this 100 kilodalton glycoprotein is the same as that of the common antigenic determinant identified by present CALLA-specific antibodies. Antibodies to different regions of this molecule may also have effects on the function of antigen-positive cells not seen with present reagents. We will further characterize the novel antigenic structures that we have recently identified on ALL cells, focusing on their cellular distribution and chemical nature. We will also study antibodies to tumor-associated antigens for their capacity to affect proliferation and differentiation of malignant cells in culture. In the year ahead, we hope to broaden the scope of our studies of cell surface antigens to include chronic lymphocytic leukemia or lymphomas. (AG)